Phonographic sound box



' W. E. C. LAU.

PHONOGRMHIC SOUND BOX.

APPLICATION FILED DEC. 8 1920.

1A1 95%, w Patented June 13,1922.

STATES WESLEY C. LA'U, OF KLEMME, IOVJA.

PHONOGRAPHIC SOUND BOX.

Application filed December 8, 1920. Serial no. 429,118.

To all whom it may concern:

Be it known that I, lVnsLnY E. C. LAU, a citizen of the United States, residing at Klemme, in the county of Hancock and State of Iowa, have invented certain new and usetul Improvements in Phonographic Sound Boxes, of which the following is a specification, reterence being had to the accompanying drawings.

This invention relates to phonographs, and particularly to the sound boxes therefor.

The general object of my invention is to provide a sound box wherein the stylus arm is not pivotally mounted upon the sound box but is itself mounted upon a somewhat flexible support which has a central opening, through which one end of: the stylus carrying arm projects, this end or extremity oi the stylus carrying arm being attached to the diaphragm to thus provide a mount for a stylus carrying arm in which there are no bearings to wear, thus transmitting the record groove impulse directly to the diaphragm without its being transmitted through a bearing.

And a further object of the invention is to so mount the stylus carrying arm or member that it is fully insulated from the body of the sound box so as not to transmit vibrations thereto.

Another object is to provide a sound box of this character so formed that foreign sounds, due to the vibrations of the sound box itself, will be almost entirely eliminated, and wherein the vibrations of the diaphragm will be transmitted to the "full extent to the tone arm but will not be transmitted to a full extent to the body of air lying against the outside face of the diaphragm.

A further object is to provide a phonographic sound box which will reproduce more accurately the actual tone recorded on the record tablet and in which this tone will be unmuttlcd and tree from harshness when reproducing high pitched voices or loud music.

Still another object is to provide means whereby the part carrying the stylus carrying needle is insulated from the sound box itself and from the diaphragm, whereby the diaphragm is insulated from contact with the body of the sound box and wherein the sound box itself is insulated from the tone arm, thus preventing vibrations being transmitted to the sound box or these vibrations in turn being transmitted to the tone arm so that the only vibrations transmitted are the vibrations of the air affected by the diaphragm itself.

Other objects will appear in the course of the following description.

My invention is illustrated in the accompanying drawings, wherein Figure lis a diametrical section through a sound box constructed in accordance with my invention, and through the tone arm connected therewith;

Figure 2 is a "face view of the sound box;

Figure 3 is a rear elevation thereof;

Figure 4 is a section on the line 44 of Figure 1;

Figure 5 is a section on the line 55 of Figure 1;

Figure 6 is a longitudinal sectional View through the joint between the tone arm proper and the neck of the sound box;

Referring to these drawings, it will be seen that the sound box body 10 is of conventional form and has the central opening 11. The rim of the sound box body is rabbeted, as at 12. The gooseneck 13 leads from the opening 11 and leads into the tone arm ortorms a continuation of this tone arm.

Disposed in the rabbeted end of the sound box is a disk 14 which is preferably of fiber or some like material, such as hard rubber or even metal, this disk being relatively stilt and being formed with. a central aperture 15 and a plurality of equi-distantly spaced apertures 16 disposed at intervals around the central aperture. Attached to this disk 14 is a stylus carrier comprising an arm 17, one end of this arm being widened and extended inward, as at 18, to rest against the fiber disk 14. This base portion 18 is perforated at a plurality of points for the reception of attaching screws or nuts 19. This arm 17 adjacent the portion 18 is formed with an outwardly projecting stylus socket 20, in which a stylus 21 may be disposed, this stylus being held in place by means of a set screw 22. This socket may be circular in form or it may have a flat side, and the stylus may have its shank circular in form or flat on one side, as illustrated in Figure 5, the stylus in the latter case being held from any rotation and it being necessary to insert the stylus in a particular manner into the socket.

The fiber disk 14 is disposed upon annular gasket 23, areterably circular in cross section. It will be seen that the fiber disk 14 is slightly less in diameter than the interior diameter of the sound box so that it rests against this gasket. The fiber disk is held in position against this gasket by means of the ring 24% which fits against a gasket 24; in the rabbet 12 and the ring 24 projects inward. slightly beyond the rabbet to bear against the margin of the disk 14: and force this disk against the gasket 23. Disposed between the outer gasket 23 and the inner gasket 23 is the diaphragm 25 which may be made of mica, glass, metal, or any other suitable and usual material, and it will be seen that the extremity of the arm 17 is inwardly extended, as at 26, to engage with the center of the diaphragm 25 and is held in engagement therewith by a screw 27 or equivalent means. The stylus 21 may be in the form of the ordinary needle, but is preferably a diamond point needle such as is used for Edison disk records, a sapphire ball stylus such as used for the Pathe records, or a sapphire point stylus for use with vertical cut records other than Path, Edison, etc.

It is to be understood that this sound box is to be used for playing vertical cut records, and in order that the needle may be held in proper position with relation to the vertical cut record, it is necessary that the sound box be disposed at an angle to the facial plane of the record, and in order that the sound box may ride close to the record yet with ample clearance, the lower part of the case or sound box proper 10 is cut away, as shown r in Figure 2 and indicated by the numeral 28, and the same part of the retaining ring 24 and the gasket 24 between this ring and the rabbeted seat 12 is also cut flush with the case or sound box 10. Preferably the tone arm 13 is adjustably connected to the sound box, and to this end a sleeve 29 is disposed within the extren'iity of the tone arm, fitting snugly within this extremity, this sleeve having outwardly projecting flanges 30 at its outer ends. Between this flange 30 and the sound box there is disposed a rubber gasket 31., and screws or like fastening means 32 pass through the flange 30 and this gasket and into the sound box. Thus the sound box is held in engagement with the sleeve 29 but sound insulated therefrom so that vibrations will not be transmitted to this sleeve and thus will not be transmitted to the tone arm. This tone arm may be split and provided with means, as for instance the clamp screw 33, passing through ears on the tone arm whereby the extremity of the tone arm may be clamped tightly upon the sleeve 29, and when this clamp screw is released, the clamp 29 may be retated or otherwise adjusted in the tone arm. Of course, I do not wish to be limited to this, and the extremity of the tone arm might connect directly to the sound box by the means illustrated for connecting the sleeve fectly, and as the amount of this bend or curvature will change according to the size of the machine or length of the tone arm, it is best to have the tone arm adjustable, as shown in Figure 6. It will be seen that a sound box constructed in accordance with my invention has very few parts, that there are no bearings to wear, and that the record groove impulse is taken directly to the diaphragm Without being transmitted through a bearing to the sound box. Thus wear on the records is reduced, foreign sounds'are almost entirely eliminated, and the actual tone produced is, I have found in practice, much better, particularly when reproduc ing high pitched voices or loud music. This is due to the more rigid construction which does not allow the needle to drag more or less in the different parts of the record. This more rigid construction is made possible because no part of the impulse is lost in a bearing. At the same time a satisfactory volume of sound is produced.

It will be seen that the position of the stylus carrying arm permits the stylus to take its impulse accurately from the record groove, this stylus being in a straight line playing position at all parts of the record. The stylus arm supporting disk is insulated, being made of fiber or like material, which is not particularly responsive to sound vibrations. It is further insulated by the circular gasket between it and the diaphragm, and the retaining ring is insulated by the gasket 24 bearing upon the outer face of the fiber disk. Furthermore, the whole sound box is insulated from the tone arm by the gaskets 31. It will be noted that the stylus supporting disk shields the center of the diaphragm, and thus the outside face of the diaphragm does not cause audible air vibrations. The apertures in the fiber disk which supports the stylus arm serve to equalize the atmospheric pressure on both sides of the diaphragm, making it unnecessary to cut away that portion of the fiber disk which is directly opposite the opening in the sound box. The fiber disk serves to protect the diaphragm from damage if the sound box is accidentally dropped or bumped, for the reason that the stylus carrying arm is in close proximity to the fiber disk 14 and this will absorb most of the shock, while the diaphragm 25 will. flex sufliciently without being damaged to allow the stylus carrying arm to swing against the fiber disk.

It is to be particularly noted that the rivet connecting the base 18 of the stylus arm 16 to the fiber disk constitutes in eifect a hinge support for the stylus arm which will permit the stylus arm to vibrate freely the fiber disk 14. being of sufficient resiliency as to permit the vibration of the stylus-carrying arm.

I claim 1. A sound box, a diaphragm therein, a disk of thin but relatively stiif, resilient material mounted upon the sound box exterior to the diaphragm and having a relatively small central aperture, and a stylus carrying member having at one extremity an inwardly projecting portion extending through the aperture in the disk and connected to the diaphragm, the opposite extremity resting upon and being attached to the disk, that portion of the stylus carrying member between the said extremities being in spaced relation to the disk, said stylus carrying member having an outwardly extending stylus receiving socket.

2. A sound box, a diaphragm therein, a. disk of relatively resilient but thin material supported upon the sound box in spaced relation to the diaphragm and having a relatively small central aperture, a stylus carrying member attached to the face of the disk and at its inner end being angular-1y bent and extending through the central opening of the disk and connected to the diaphragm, the outer end portion of the stylus carrying member having means for support ing the stylus.

In testimony whereof I hereunto affix my signature.

W'ESLEY E. C. LAU. 

